Background f.lux automatic color change - my eye see this 3 sec..

Why is a fast temp change colors? I see this change, should not it be so that it would not be visible to the eye?
Please update and fix this.

Within 3 seconds of the normal color the temperature changed to another. This difference was noticeable.
I understand that this is a free program, but for so many years developing this shit it is still a mess. ;]